Cylindrical air filter with radially directed seal and method of manufacturing a housing for same

ABSTRACT

An air filter has a tubular metal housing with an air inlet and a plastic end cap affixed to one end of the housing. The opposite end of the housing is enclosed by a removable cover. The plastic end cap has an integral cylindrical air outlet with a portion thereof extending into the tubular housing. A generally cylindrical air filter element includes an inner liner, an outer liner, filter media captured therebetween, a closed end and an open end. The open end of the filter element has an end cap formed of an elastomeric material with an opening defined by a generally cylindrical radially inward-facing surface. The diameter of the opening is smaller than the outside diameter of that portion of the outlet member of the end cap that extends into the housing. The filter element is mounted on that portion of the outlet member extending into the tubular housing and the elastomeric material provides a seal.

This application is a continuation of application Ser. No. 09/178,661,filed Oct. 26, 1998, and issued as U.S. Pat. No. 6,187,240. ApplicationSer. No. 09/178,661 is a continuation of 08/878,399, filed Jun. 18,1997, and issued as U.S. Pat. No. 5,863,313. Application Ser. No.08/878,399 is a continuation of application Ser. No. 08/675,081, filedJul. 3, 1996, and issued as U.S. Pat. No. 5,693,109; application08/675,081 is a continuation of application 08/189,890, filed Jan. 21,1994 and issued as U.S. Pat. No. 5,547,480. The disclosures of09/178,661; 08/878,399; 08/675,081; and 08/189,890 are incorporatedherein by reference.

BACKGROUND OF THE INVENTION

The present invention relates generally to air cleaners or air filtersand more specifically to air cleaners with cylindrical pleated paperfilter elements which are used primarily on the over-the-road trucks andagricultural vehicles. Such applications generally are severe filteringenvironments.

U.S. Pat. No. 3,078,650 shows one prior art structure of air cleaner ofthis type. The air cleaner has a tubular metal housing with an inlet fordust laden air. A cylindrical pleated paper filter element is mountedwithin the housing. A clean air outlet communicates with the interior ofthe pleated paper filter element. A seal must be provided between thepleated paper element and the outlet so that the dust laden inlet airwill be forced through the pleated paper media of the filter wherebyparticulates are removed from the air flow before it exits from thefilter. In the '650 patent the seal between the filter element and theoutlet is provided by a gasket secured to the filter element. The gasketengages an end wall of the tubular housing with the filter element heldin place by a yoke and associated bolt and nut assembly.

U.S. Pat. No. 4,720,292 discloses another prior art structure for acylindrical air filter of the type of the present invention. In itspreferred embodiment, the housing of the '292 air filter is formed of aplastic material. A cylindrical pleated paper filter element is mountedwithin the housing. The pleated paper element has an open end for fluidcommunication with the air outlet. The open end of the filter elementhas a ring like end cap that is preferably made from an elastomer suchas urethane foam which has a relatively soft, rubber-like consistency.The air filter element is mounted on the air outlet tube, and a seal isprovided by engagement of the end cap with the tubular outlet member.

In order to manufacture an air filter using a plastic housing, a moldfor the housing is typically needed. A separate mold would typically beused for housings that vary in size as well as variations in location ofthe air inlet. The tooling for molds for each possible application ofthe air filter can be quite expensive.

SUMMARY OF THE INVENTION

The air cleaner of the present invention incorporates a tubular housingwith an open end and an air inlet. An end cap is affixed to and enclosesthe open end of the tubular housing. The end cap has a generallycylindrical portion extending into the interior of the tubular housing.The filter element is generally cylindrical with an inner liner, outerliner and filter medium sandwiched there between. The filter element hasan end cap formed of elastomeric material. The end cap has an openinginto the interior of the filter element. The opening is defined by agenerally cylindrical radially inward-facing surface with the openinghaving a diameter that is smaller than the outside diameter of theportion of the end cap that extends into the housing. The filter elementis attached to the end cap by inserting the outlet portion of the endcap into the opening defined in the end cap of the filter element. Theend cap of the filter element and the outlet portion of the end capaffixed to the housing provide a seal. A cover is removably mounted toenclose the second end of the tubular housing.

In the preferred embodiment the tubular housing is formed of a suitablemetal material and the end cap is a molded plastic. The metal housing isprovided with a plurality of engagement members positioned about itsfirst end and projecting inwardly. The plastic end cap has a pluralityof recesses formed therein which are adapted to receive the engagementmembers to affix the end cap to the housing.

The present invention also relates to a method of manufacturing thehousing of the preferred embodiment of the invention. It includes thesteps of forming a tubular housing from a metal material with thetubular housing having first and second open ends and an air inlet. Aplastic end cap is molded with an integral air outlet and a plurality ofrecesses in its outer circumference. The end cap is then inserted intoone end of the metal housing. Engagement members are formed in thetubular housing to project inward into the recesses in the plastic endcap to affix the end cap to the housing.

Thus, in its preferred embodiment the present invention provides theadvantages of a metal housing for air filters particularly designed forrugged environments and a filter element seal structure eliminating themechanical arrangement such as that shown in the '650 patent describedabove. These and other advantages of the present invention will becomeapparent with reference to the accompanying drawings, detaileddescription of the preferred embodiment, and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view in perspective of the air filter of the presentinvention;

FIG. 2 is an elevational view in partial section with portions removed;

FIG. 3 is an enlarged fragmentary view in section illustrating theattachment of the end cap to the housing of the air filter of thepresent invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings wherein like numerals represent like partsthroughout several views, there is disclosed in FIG. 1 an air cleaner orfilter 10. Air cleaner 10 is a generally tubular housing 12 with a firstend 14 and a second end 16. In the preferred embodiment housing 12 isformed of a suitable metal material. Housing 12 has an air inlet 18defining an opening 20 for the introduction of particulate laden airinto filter 10. An end cap 22 is affixed to housing 12 at first end 14to enclose first end 14 as will be described in more detail hereafter.End cap 22 is a generally planar circular base member 24 with anintegral ring member 26 disposed at its outer circumference and enclosedwithin housing 12. A second ring member 28 is also formed integrallywith base member 24 and positioned within housing 12. Ring members 26and 28 are concentrically disposed with respect to each other. Alsointegrally formed with base member 24 is an air outlet 30 extendingabove the exterior surface of end cap 22. Air outlet has a tubularportion 32 extending into the interior of housing 12. Air outlet 30defines an opening at 34 through which filtered air exits from airfilter 10.

Disposed within housing 12 is an air filter element 36. Air filterelement 36 is of the type disclosed in U.S. Pat. No. 4,720,292, thedisclosure of which is incorporated herein by reference. It is acylindrical element having a cylindrical liner 38 and a cylindricalouter liner 40, both constructed from perforated metal. A cylindricalpleated paper filter element 42 is mounted between liners 38 and 40.Element 36 has a closed end 44 in the form of a circular cap of urethanefoam material molded thereon and having a relatively soft, rubber-likeconsistency. Closed end 44 is molded over and holds together the ends ofliners 38 and 40 and filter element 42 and extends across the end offilter element 36 to provide a closed end.

Air filter element 36 has an open end disposed adjacent end cap 22. Aring-like end cap 46 is molded over the ends of liners 38, 36 andpleated paper filter element 42. End cap 46 is preferably made from anelastomeric material such as urethane foam material having a relativelysoft, rubber-like consistency so that it is capable of functioning as aseal or gasket material. End cap 46 has a radially inward facing surface48 adapted to engage the outer surface of tubular portion 32 of airoutlet 30. Surface 48 defines a generally cylindrical opening with aninner diameter which is slightly smaller than the outside diameter oftubular portion 32. Thus, the elastomeric material of end cap 46 iscompressed at surface 48 to provide a positive air seal between end cap46 and air outlet 30. The open end of air filter element 36 is alsocaptured between tubular portion 32 and second ring member 28 toproperly position air filter element 36 within housing 12.

Second end 16 of housing 12 is enclosed by a cover 50 which is removablymounted to housing 12. Cover 50 has an end member 52 and a side wall 54.Extending around side wall 54 is a ledge member 56. At second end 16 ofhousing 12, a flange portion 58 is provided which is received on ledgemember 56. Cover 50 has a plurality of spring-loaded clamps 59, thestructure of which is well known in the prior art, which engage flangeportion 58 to secure cover 50 thereto. End member 52 of cover 50 engagesthe closed end 44 of air filter element 36. Cover 50 may also beprovided with a particulate collection trap (not shown).

As shown in more detail in FIGS. 2 and 3, ring member 26 of end cap 22provided with a plurality of recesses 60 spaced about its circumference.At it first end 14, housing 12 has a plurality of inwardly projecting 20members 62 that mate with and are received within recesses 60 to affixend cap 22 to housing 12. As previously described, in the preferredembodiment end cap 22 is formed of a plastic material, such aspolypropylene, while housing 12 is constructed of metal. Removable cover50 may be either plastic or metal. Housing 12 and end cap 22 areconstructed in the following manner. Metal housing 12 is made inaccordance with well known prior art processes to the appropriate lengthand with air inlet 18 disposed at the desired location. End cap 22 ismolded from a plastic material according to well known moldingprocesses. End cap 22 is placed on first end 14 of housing 12 in asnap-fit frictional engagement. Housing 12 is stamped or indented inwardabout first end 14 at locations. corresponding to recesses 60 in ringmember 26. This metal stamping operation forms inward projections 62that are received in recesses 62 to affix end cap 22 to housing 12. Airfilter 10 is further assembled by installing air filter element 36within housing 12 and attaching cover 50.

From the above description, it can be seen that the present invention inits preferred embodiment incorporates the advantageous seal structure ofthe '292 patent. The housing can be made according to various designspecifications by a metal forming process eliminating the need andexpense of designing a plastic mold for each filter configuration.Moreover, the seal arrangement eliminates the mechanical structure usedin air cleaners of the type shown in the U.S. Pat. 3,078,650.

Although a preferred embodiment of the invention has been disclosed, itshould be understood that the same is capable of modification withoutdeparture from the scope and spirit of the invention as defined in thefollowing claims.

What is claimed is:
 1. An air cleaner comprising: (a) a metal housingincluding an air inlet tube, the metal housing defining a centralinterior region and having an open first end and an open second end;and, (b) a first molded plastic end cap positioned in covering relationon a first end of the tubular metal housing; (i) the first moldedplastic end cap including: (A) an air outlet tube projecting outwardlyfrom an exterior surface of the molded plastic end cap; (B) an innertubular portion extending into the housing central region and definingan outlet tube for air flow outwardly from the metal housing centralregion; and, (C) a first ring member disposed along an outercircumferential region of the molded plastic end cap and projecting intothe central region of the air cleaner; (c) the first molded plastic endcap being secured to the metal housing by a securing arrangementcomprising a frictional engagement.
 2. An air cleaner according to claim1 wherein: (a) the securing arrangement includes engagement between aportion of the metal housing and a portion of the first ring member. 3.An air cleaner according to claim 2 wherein: (a) the frictionalengagement includes at least one projection on the metal housingengaging a portion of the first molded plastic end cap.
 4. An aircleaner according to claim 3 wherein: (a) the frictional engagementincludes a plurality of projections on the metal housing engaging aportion of the first molded plastic end cap.
 5. An air cleaner accordingto claim 3 wherein: (a) the frictional engagement includes at least oneprojection on the metal housing engaging at least one recess in thefirst molded plastic end cap.
 6. An air cleaner according to claim 5wherein: (a) the frictional engagement includes a plurality ofprojections on the metal housing engaging a plurality of recesses in thefirst molded plastic end cap.
 7. An air cleaner according to claim 2wherein: (a) the first molded plastic end cap includes a second ringmember projecting into the metal housing central region; the second ringmember being oriented between the inner tubular portion and the firstring member.
 8. An air cleaner according to claim 7 including: (a) acover removably secured over the open second end of the metal housing.9. An air cleaner according to claim 8 wherein: (a) the cover removeablysecured over the open second end comprises plastic.
 10. An air cleaneraccording to claim 9 wherein: (a) the cover removeably secured over theopen second end is secured on the metal housing by a plurality ofclamps.
 11. An air cleaner according to claim 7 including: (a) a filterelement removeably mounted in the metal housing central region.
 12. Anair cleaner according to claim 11 wherein: (a) the filter element is acylindrical element sealed to the inner tubular portion of the firstmolded plastic end cap.
 13. An air cleaner according to claim 12wherein: (a) the filter element is positioned in the air cleaner with:(i) the inner tubular portion of the first molded end cap extending intoan interior of the cylindrical element; and, (ii) the second ring memberof the first molded end cap circumscribing an end of the filter element.14. A method of assembling an air cleaner, including a step of: (a)securing a molded plastic end cap to a metal housing sidewall by anattachment step comprising a friction fit engagement between the metalhousing sidewall and the molded plastic end cap; (i) the molded plasticend cap having: an exterior surface with an air outlet tube projectingoutwardly therefrom; an inner surface portion with an inner tubular airflow tube projecting therefrom; and, a first ring member extending fromthe inner surface of the molded plastic end cover and circumscribing theinner tubular air flow tube; (ii) the step of securing including: (A)orienting the molded plastic end cap with the inner tubular air flowtube and the first ring member projecting into an interior defined bythe metal housing sidewall.
 15. A method according to claim 14 wherein:(a) said step of securing by an attachment step comprising friction fitengagement includes providing a projection on the metal housing toengage a portion of the first ring member on the molded plastic end cap.16. A method according to claim 15 wherein: (a) said step of securingincludes providing a plurality of projections on the metal housing inengagement with a plurality of recesses on the molded plastic end cap.